Fuel injection pump



Sept. 5, 1944. c. w, rRuxELl., JR

FUEL INJECTION PUMP Filed July 25, 1942 3 Sheets-Sheet 1 Suunto: .QZZwZ/z c. w. TRUXELL, JR 2,357,563

FUEL INJECTION PUMP Sept. 5, 1944.

s sheets-sheet 2 Filed J'uly 23, 1942 Patented Sept. 5, 1944 FUELINJECTION PUMP Clyde w. Truxell, Jr., No1-twine. Mich., assigner toGeneral Motors Corporation, Detroit, Mich., a corporation of 'DelawareApplication July 23, 1942', serial No. 452,051

9 claims.

This invention relates to plunger pumps with a plurality of ports in thecylinder wall, from different ones of which fluid is delivered atdifferent points in the stroke of the plunger.

It relates particularly to such plunger pumps for supplying meteredquantities of liquid fuel from a single pump cylinder, successively todif- -ferent cylinders of an internal combustion engine.

The object of the invention is a pump with a plurality of delivery portsand a relief port, and a plunger cooperating with the cylinder to putthe pump chamber in communication with the different delivery ports indifferent positions of reciprocation of the plunger, there being meansindependent of the pump plunger for closing ythe relief port todetermine the periods ofdelivery through the different delivery ports.

`Another object vof the invention is a pump comprising a plurality ofplungerpumps of the foregoing kind, with a single rotaryl valve meanscommon to all the cylinders driven in timed relatonship to the plungersand adapted to close the relief port of each cylinder a plurality oftimes,

in the delivery stroke of each plunger, to determine the successiveperiods of delivery through the different delivery ports.

A still further object of the invention is a pump structure of theforegoing kind in which the relief port of each cylinder is a combinedinlet and relief port which is only closed by the rotary valve meansduring the periods of delivery from the cylinder pump chamber, and is atall other times open to permit-a free iiow of liquid fuel to and frobetween the cylinder and the source of fuel supply.

The above and other objects of the invention will be apparent 'as thedescription proceeds.

- According to the invention, the combined inlet and relief port of eachcylinder opens into the pump chamber at a point unswept by the'pumpplunger, while the delivery ports are longitudinally spaced and swept bythepump plunger which has an annular groove intermediate its ends and incommunication with the pump chamber; the delivery port through whichdelivery nrsttakes place communicates directly with lthe pump chamber inthe nrst part onf the delivery stroke of the plunger and is then coveredby the end of the plunger, while the delivery port through whichdelivery next occurs is placed inv communication with the pump chamberthrough (Cl. 10S-173) nular groove in its periphery interrupted by aplurality of land areas to close the combined inlet and relief port ofeach cylinder a plurality of times in each revolution of the rotaryvalve member. The grooved area of the rotary valve member is adapted toput the combined inlet and relief port is communication with the sourceof sup'- plyl and this communication is only stopped as and when a landarea closes the combined inlet and relief port to cause delivery of uidthrough one or another of the different delivery ports.

In a -pump unit, comprising a plurality of plunger pumps of theforegoing kind, the cylinders are conveniently arranged parallel to eachother, in a circle, with their combined inlet and relief portsradiatingin.v uniform angularly spaced relationship from a cylindrical centralchamber containing the rotary valve member common to them all. Therotary valve member turns once in the time taken for all the pumpplungers to lcomplete one cycle oi' movement and it must lhave as manyland areas as there are delivery portsin each pump cylinder. The anglebetween the leading edges of the lands on the valve member may be equalto 360 divided by the number of pump cylinders and the number ofdelivery the annularl groove in the plunger. The rotary v multiple ofthe resulting figure which is neither a whole number multiple nor awhole number factor of the angle between relief ports. A11 the landsmust traversethe relief port of a given cylinder during the time theplunger of that cylinder is on its delivery stroke. If all the lands arecontained in less than half the circumference of the valve member thepump plungers can be driven by a simpi wobble plate with suction anddelivery strokes extending through equal intervals of time and eachthrough 180 of rotation of the wobble plate.

The drawings show the application ofthe in- -vention to a pump unitsuitable .for supplying metered quantities prf fuel to the respectivecylinders of a twelve cylinder internal combustion engine, andcomprising six plunger pumps each of which has two delivery ports. It isdriven at the speed of the engine cam shaft (engine speed `in the caseof a two-cycle engine and half engine speed in the case of a four-cycleengine) giving one delivery. to a different cylinder every. 30 :of

crankshaft rotation in the case of atw'o-'cycle engine and every ofcrankshaft rotation vin the case of a four-,cycle engine.

In the drawings l Figure 1 is a longitudinal sectional view on 'lineI--I ofFlgure 2.

Figure 2 is a view on line 2--2 of Figure l.

Figure 3 is a sectional view on line 3-3 of Figure 1.

Figure 4 is a sectional view online 4-4 of Figure 3.

Figurel is a development of the rotary valve member showing theassociated inlet and relief ports radiating from the cylindrical centralchamber superimposed in dotted outline.

The pump lbody is conveniently formed of a number of suitable sections Ito 5 secured together.

The end section I and the section 2 are secured together by studs 1 withnuts, and are bored axially to provide a housing for the pump drivingmeans and bearing support for the driving shaft 8 thereof. The sections42 and 3 are secured together by studs 9 with nuts, while the sections 3and 4 are secured together by tubular studs Iii with locknuts I andarebored axially for a liner providing a central low pressure fuel chamberI2 within which the rotary valve lmember I4 rotates. The section 3 isalso bored for six cylinder barrels I to 20 arranged in uniformly spacedrelationship in a circle concentric with the cylindrical central chamberand containing plungers 25 to 3|!V respectively provided with plungerfollowers 35 to 40 slidable in corresponding but larger bores inthesection 2. The cap section 5 is a housing for a rack 42 and pinion 43 bywhich the rotary valve I4 may be axially moved. It is secured to thesection 4 by screws 44.

The sections I and 3 of the pump body are preferably of steelforirequisite strength while the sections 2, 4, and 5 are of aluminumfor lightness.

Three mounting lugs 41 (Figures 2 and 3) lare provided on the section Ifor securing the pump body to the frame or gear case 48 (Figure 1) of atwelve-cylinder internal combustion engine (not otherwise shown), whileat the opposite end of the pump body on the section `3 is a stud 49(Figures .2 and 3) by which it may be secured to any suitable outer endsupport.

The inner end of lthe driving shaft 8 is supported in a bushing 50 inthe body section 2 vwhile the outer end is supported in a ball bearing.5| of which the inner race 52 is secured to :the shaft 8 and the outerrace 53 is secured in loWers are/resiliently urged towards the wobbleplate by springs such as 1|, vthus maintaining the attened areas of theballs which have universa] movement in their sockets, in contact withthe wobble plate.

It will be appreciated that while the wobble plate 64 and the outerraces 6|) and 6| are capable of. rotation, they are normally preventedfrom revolving by the frictional forces between these parts and betweenthe at faces of the balls 61 and the wobble plate which merely wobblesand drives the plungers on their delivery strokes as the shaft 8 isturned by gearing from the engine crankshaft (not shown) to a gear wheel14 splined on the outer end of the shaft 8 and secured thereto by a nut15.

The inner end of the shaft 8 is internally splined asat 16 (with an oddflat for indexing purposes) to provide a driving connection to thereduced and externally splined end 11 of the rotary valve member I4,which is capable of axial movement relatively to the shaft 8.

' Each of the plungers 25 to 30 is provided with an annular groove suchas 8U in its periphery at a point removed from its end, said annulargroove vbeing in communication with the pump chamber through drilledducts 8| communicating with a bore 82 in the end of the plunger. Theopposite ends of the plungers are bored ,for lightness as at 83.

The pump chambers of the cylinder barrels I5 to 20 are closed by plugssuch as 85 which are held in position by the section 4 of the pump body.

The pump chamber of each cylinder barrel at a point unswept by theplunger is provided with a combined inlet and relief port 81, saidrespective ports 81 lying in a plane normal to the axis of the rotaryvalve member and radiating in uniform angular-ly spaced relationship at60 to each other from the central chamber I2 common to them all.

Each cylinder barrel has a pair of longitudinally spaced delivery portssuch as 9| and 92 (Figures 3 and 4) through the side of the cylinderbarrel at points swept by the plunger. The. ports 9| and 92 radiate fromtheirV respective cylinder barrels outwards in the section 3 of the pumpcasing, at an angle to each other, respectively to connect with drilledextensions therein of the tapped holes for an adjacent pair of thetubular studs I0 which constitute delivery outlets of which there are atotal of twelve arranged in uniformly spaced relationship in a circle.

The tubular studs Il) are screw threaded throughout their length and arein screw threaded engagement with both thesections 3 and 4 of the pumpbody in which they are locked by the lock nuts I0.

Pipes such as 94 are connected to each delivery outlet I0 by nipplessuch as 95 and serve to conduct fuel therefrom to spring loadedinjection valves for the respective cylinders of the engine (not shown).

The rotary valve member I4 has an annular groove |00 in its periphery,interrupted by two land areas IUI and |02. The land areas are tapered inwidth between their leading and following edges, the leading edges ofboth being parallel to each other and 90 apart as measured in a planenormal to the axis of the rotary valve member, and the following edgesof both being similarly spaced and .parallel to each other, as

best shown in Figure 5.

Fuel from a low pressure source of supply (not shown) is conducted intoand out of the central chamber I2 between the annular groove |00 and theinner wall of the liner through the bores |04 and |05.

The combined inlet and relief ports 81 of each cylinder barrel maintaincommunication between the central chamber I2 and the pump chambers atall times, except as the lands IUI and |02 move successively over eachof the inlet and relief ports 81 and interrupt such communication duringparts of the periods in which each pump chamber is open to one or theother of its delivery ports.

The delivery ports 9| and 92 of each pump cylinder lare so spacedlongitudinally 6i the reand 4 for conveying the lubricating oil throughspective, cylinders that one of them communi- L cates directly with thepump chamber in the rst part of the delivery stroke of the plunger andAis then covered by the end of the plunger, while the other delivery portis placed in communication with the pump chamber through theannularrelief ports of each cylinder twice in each vrevolution of therotary valve member and willdetermine the periods of delivery in arepeating cycle first through the uppermost delivery porty of a givencylinder and then through the lowermost delivery .port of the cylindernext behind in the 'direction of rotation of the rotary valve member,

and thus in alternatingprogression through each delivery port of all thecylinders oncel in every revolution of the valve member and the wobbleplate and providing a total of twelve deliveries wat 30 intervals inevery revolution thereof.

The number of degrees of rotation through which the combined inlet andrelief ports 8l are closed by Ythe lands4 lill and |02 and hence thequantity of fuel delivered through the delivery ports 9|, 92 depends onthe width o fthe lands opposite the ports 8l.

Since the4 lands are tapered in width, axial adjustment of the rotaryvalve member ld will ,vary the quantity of fuel delivered through thedelivery ports.

It is obvious that the land areas Iiil and |82 may be tapered uniformlyor irregularly, sym

metricallyv or unsymmetrically or infany desired way. As shown mostclearly in Egure 5,the leading and following edges of 'the lands areequally but oppositely inclined to vtheir axis of rotation and taperuniformly towards their narrower ends to 4provide for earlier closingwith later opening of the combined inlet and relief ports 8l orvinefversa, and thus increasing or reducing the quantity of fueldelivered successively through the respective delivery .ports 9| and 92in dependence onl the extent to which the` rotary yalve member is movedin one direction or the other axially of the liner Il.

'Iu'he `outer end of the rotary valve member' I4 .is reduced in diameterand grooved to forma s stud head |06 thereon, which loosely nts in a Tslot ina piece |08 secured to the end of the rack A2 by a pin.|09, andforming a coupling which permits the rotary valve member to rotate whilebeing held in any desired position of axial adjustment by the yrack 42,the position of which is controlled by the pinion 43. o

As shown in Figure 2,.'the pinion 43 is mounted on a shaft I having aserrated end I by which it may be turned manually or automatically bythe engine governor (not shown) to vary th quantity of fuel supplied tothe engine. i

"Referring now to Figure 4,;a ductA ||screw the short ducts |8 and 9 tothe annular grooves and |2I, |22, and thence to the bearing surfaces ofthe rotary valve member |4, also through the short duct |24 to theannula'lflgroove |25 and thence to the shaft 8 in the bearing 50, andfrom the annular groove |22 through ducts such as |26 to each of theplungers 25 to 30. From the annular groove |25 there are short ductssuch as |21 to each of the plunger followers 35 to 40.

s The ball bearings 5|, 58, and 59 and the balls such as 6J in theirsockets are lubricated by oil in the housing which is retained thereinat a level above the axis of the shaft 8.

I claim:

1. A plunger pump including a cylinder having a plurality of spaceddelivery ports and a relief port, a plunger in the cylinder, saidplunger cooperating with said delivery ports to place the pump chamberin communication selectively with dierent delivery ports in differentpositions of reciprocation of the plunger, and means independent of thepump plungerv for closing said relief port and determining the periodsof delivery through said different delivery ports.

2. The combination according to claim 1 in whichthe means for closingsaid relief port is a rotary valve operated in timed relationshipvto jthe plunger.

3. A plunger pump including a cylinderhaving a pluralityy of deliveryports and a relief port, a plunger in the cylinder, said plunger andsaid cylinder cooperating to place the pump chamber in communicationwith different delivery ports alternately and successively in differentpositions of reciprocation of the plunger and means independent of thepump plunger for closing said relief port to determine the period ofdelivery through said' different delivery ports; said plunger .having anannular groovesintermediate Aits ends and in communication with thepump'` chamber; that delivery port through which delivery first takesplace communicating directly with the pump chamber in the ilrst part ofthe delivery stroke of the plunger and then being covered by the end ofthe plunger while that delivery port through which delivery next occursis placed in communication with the pumpchamber through the annulargroove in the plunger.

4. A plunger pump including a cylinder having first and second deliveryports and a relief port,

, a plunger in the cylinder, said plunger and said cylinder cooperatingto place the pump chamberv `chamber; said first delivery portcommunicating directly with the pump chamber in the first part ofthedelivery stroke of the plunger and then threaded for aplpecohnectionto a supply of lubricating oil (not shown) is provided in thesection 3. The duct ||5 is connected to a longi" tudinal duct I6extending into the sections 2 being covered by the end of the plungerwhile lthe second delivery port is placed inl communication with thepump chamber through the an nular groove in the plunger.

5. A pump comprising, in combination, a plurality of plunger pumps eachincluding a cylinder having a plurality of delivery ports, a relief\port,.and a plunger cooperative to place .the

pump chamber of itscylinder in communication w with different deliveryports during. its vstroke movement,V means independent of the pumpplungers for closing said relief ports to determine the periods ofdelivery through said different delivery ports and means forreciprocating said plungers and driving the relief port closing means intimed relationship.

6. A pump comprising, in combination, a body having a plurality ofparallel pump cylinders arranged in a circle and in uniformly spacedrelationship, a central low pressure fluid chamber, a combined inlet andrelief port for each cylinder, said combined inlet and relief portsradiating in uniform angularly spaced relationship from said centralchamber, a plurality of longitudinally spaced delivery ports in each ofsaid cylinders, a plunger in each of said cylinders, said plungers beingcooperative with their respective cylinders to place their pump chambersalternately in communication with the different longitudinally spacedvdelivery ports during their stroke mvement, a rotary valve member insaid central chamber, and means for driving said valve member and saidplungers in timed relationship; said valve member being adapted to closesaid combined inlet and relief ports to determine the periods ofdelivery through said different delivery ports respectively of eachcylinder,

7. The combination according to claim 6 in which the rotary valve memberhas an annular groove in its periphery interrupted by as many land areasas there are delivery ports in each of said cylinders, said grooved areabeing adapted to put the combined inlet and relief ports incommunication with the central chamber, and each of said land areaseffecting closure of said combined inlet and relief ports of eachcylinder once in each revolution of the valve member.

8. The combination according to claim 6, in which each cylinder has apair of longitudinally spaced delivery ports and the rotary valve memberhas an annular groove in its periphery interrupted by two land areas,said grooved area being adapted to put the combined inlet and rcliefports in communication with the central chamber, and said land areaseffecting closure of said combined inlet and relief port of eachcylinder twice in each revolution of the rotary valve member.

9. A pump unit comprising six parallel pump cylinders arranged inuniformly spaced relationship in a circle, a central low pressure iiuidchamber, a combined inlet and relief port for each cylinder, saidcombined inlet and relief ports radiating at to each other from saidcentral chamber, a pair of longitudinal spaced delivery ports in each ofsaid cylinders, a plunger in each of said cylinders, said plungers beingcooperative with their respective cylinders to place their pump chambersin communication with one and the other of the delivery ports of eachcylinder alternately during their stroke movement, a rotary valve memberin said central chamber, said rotary valve member having an annulargroove in its periphery interrupted by two land areas with leading edgesspaced apart as measured in a plane normal to the axis of the rotaryvalve member, and means for driving said valve member and said plungersin timed relationship including a wobble plate, turning at the samespeed and in the same direction as the valve member for driving saidplungers; said land areas of said valve member successively effectingclosure of said combined inlet and relief port of each cylinder twice ineach revolution of the rotary valve member to determine the periods ofdelivery in a repeating cycle rst through a delivery port in a cylinderin advance and then through a delivery port in the cylinder next behindin the direction of rotation of the rotary valve member and thus inalternating progression through each delivery port of all the cylindersonce in every revolution of the valve member and the wobble plate, and atotal of twelve deliveries at 30 intervals in every revolution thereof.f

CLYDE W. TRUXELL, Jn.

